The Williams Institute at UCLA School of Law, a gay and lesbian think tank, released a study in April 2011 estimating based on its research that just 1.7 percent of Americans between 18 and 44 identify as gay or lesbian, while another 1.8 percent -- predominantly women -- identify as bisexual. Far from underestimating the ranks of gay people because of homophobia, these figures included a substantial number of people who remained deeply closeted, such as a quarter of the bisexuals. A Centers for Disease Control and Prevention survey of women between 22 and 44 that questioned more than 13,500 respondents between 2006 and 2008 found very similar numbers: Only 1 percent of the women identified themselves as gay, while 4 percent identified as bisexual.
Higher numbers can be obtained when asking about lifetime sexual experiences, rather than identity. The Williams Institute found that, overall, an estimated 8.2 percent of the population had engaged in some form same-sex sexual activity. Put another way, 4.7 percent of the population had wandered across the line without coming to think of themselves as either gay or bisexual. Other studies suggest those individuals are, like the bisexuals, mainly women: The same CDC study that found only 1 percent of women identify as lesbian, for example, found that 13 percent of women reported a history of some form of sexual contact with other women.
"Estimates of those who report any lifetime same-sex sexual behavior and any same-sex sexual attraction are substantially higher than estimates of those who identify as lesbian, gay, or bisexual," the Williams Institute's Gary J. Gates concluded.
Of course, gays aren't the only minority population that has an outsized place in the public imagination. Americans also "vastly overestimate the percentage of fellow residents who are foreign-born, by more than a factor of two, and the percentage who are in the country illegally, by a factor of six or seven," according to a 2012 Wall Street Journal report on the social science of estimating minority groups. In 1993, a group of political scientists reported in Public Opinion Quarterly that "The extent to which minority populations are perceived as a kind of threat is ... related to perceived proportions, though the direction of causality cannot be determined." Correcting the misimpressions about the size of a minority group hasn't been proved to have much impact on beliefs about them in the short-term, but that doesn't mean that they might never.
One thing's for sure: it's hard to imagine the fact that so many think the country is more than a quarter gay or lesbian has no impact on our public policy.